Hard Disk Drive Failure
Robyn's PC gives her a "Hard Disk Drive Failure" error message at boot up. A reboot loads Windows.
I hate to be the bearer of bad news, but your hard drive is almost certainly dying. This is serious, and will become more so if you don't act quickly.
Everyone should regularly backup their data--at the very least. But in your case, both an up-to-date data backup and a reasonably recent image backup of the entire drive are absolutely vital. If you don't have these, buy an external hard drive and create an image backup now. (I recommend either Macrium Reflect Free or Easus ToDo Backup for this job.) Then separately backup the files you change or create every day.
Then think about replacing your internal hard drive before it dies.